Conventional typical resist materials are polymer based materials capable of forming amorphous thin films. For example, a resist thin film is made by coating a substrate with a solution of a polymer resist material such as polymethyl methacrylate, polyhydroxy styrene having an acid dissociation reactive group, polyalkyl methacrylate. A line pattern of about 45 to 100 nm is subsequently formed by irradiating the resist thin film with ultraviolet, far ultraviolet, electron beam, extreme ultraviolet (EUV), and X-ray or the like.
However, polymer based resists have a molecular weight as large as about 10,000 to 100,000 and also wide molecular weight distribution. In lithography using a polymer based resist, roughness accordingly occurs on a fine pattern surface; the pattern dimension becomes difficult to be controlled; and the yield decreases. Therefore, there is a limitation in miniaturization with lithography using a conventional polymer based resist material, and in order to make a finer pattern, various low molecular weight resist materials have been proposed.
For example, an alkaline development type negative type radiation-sensitive composition using a low molecular weight polynuclear polyphenolic compound as a main component has been suggested (for example, see Patent Literatures 1 and 2).
Also, as a candidate of a low molecular weight resist material having high heat resistance, an alkaline development type negative type radiation-sensitive composition using a low molecular weight cyclic polyphenolic compound as a main component has been suggested (for example, see Patent Literature 3 and Non Patent Literature 1). Because of their low molecular weights, these low molecular weight cyclic polyphenolic compounds are expected to provide a resist pattern having a small molecular size, high resolution, and small roughness. Also, the low molecular weight cyclic polyphenolic compounds, which have a rigid cyclic structure in their skeletons, impart high heat resistance in spite of their low molecular weights.